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Add A Hard Drive To A Failing RAID Array

There are a lot of subtle nuances to Windows Server 08. Many different configurations to get it set up the best for your particular setup, and a bevy of software to add to fill in any gaps that it doesn’t come with after a base install. One of the less talked about aspects of running a server would be failing RAID configurations. Yes there are a lot of articles and forum discussions out on the web about proper backup procedures in preparation of a failing array or drive, many on how to set up the correct RAID for your situation, and few on RAID troubleshooting.

I had a simple RAID 1 setup at work with 2 250GB WD Blues. Nothing super fast or big, but this was a reclaimed server from a project that never got off the ground and I was going to make use of it. I turned it into a AD/DNS and DHCP server which shared the load 50/50 with our primary AD/DNS DHCP server. I had replication set up between the two so I would have a 3 day old redundant set of all the companies files. This was basically my backup server that I could step up if the main server went down. But one of the drives in my main array failed and thanks to my Via RAID monitor, I can tell the array is broken and a disc has failed.

Here is a detailed article on how to tackle a broken RAID with several examples on what you could do as well as what I actually did to get it all back together.

Raid Software Is A Must

So you have your fancy new server all set up with Server 03 or 08 and it configured the way you want. You have a RAID in place, whether its 0,1,5,10 or one of the lesser used ones. No matter how well ventilated or how clean the environment is, hardware fails over time. There is nothing you can do about it except plan for a best case scenario on how to make your data safest and transferable. You have already done the first step by creating a RAID, unless you did RAID 0 which isn’t redundant, but you can’t expect it to function all by itself forever can you? Setting up a Hot Spare will definitely make your situation require a lot less attention, but what happens if multiple drives fail at the same time? Do you want to come into work greeted with the “No Bootable Device” Black screen of death?

I wouldn’t want to.

That is where your RAID software comes into play. Your RAID software has everything from creating new arrays, adding to the existing array, adding the aforementioned Hot Spare, and keeping you informed on the status of your array. The RAID controller I have is a Via VT8237 controller with its accompanying Via V-RAID Utility. The first picture in this article is of that software. Notice how it shows the array is broken on the second HDD. I would have never know this information and could have possibly lost all my data if the other HDD fails.

Fixing A Broken RAID Array

Powering off is the first step. Every time Windows Server 08 is shut down, and 03 and earlier to my recollection, it prompts you for the reason its being turned off. Some people find this bothersome, but I’m a fan as it keeps a log based on why and when it was shut down. For those of you who have zero server experience, most rack mounted servers–and some towers–have hot-swappable drive bays for easy removal and installation and can even be done on the fly as the system is still powered on. One point I would love to make here, yes SATA in all forms is hot swappable, meaning a drive can be removed and installed with the PC running.

PSU connections on the other hand, not so much.

You want to fry a mid/lower wattage PSU or motherboard, plug in a hard drive while the PC is running. That instant power draw will fry most. As to not damage any components, its a good idea to power down unless you have an external power source for your HDD. Assuming everyone knows how to install a HDD, I won’t focus too much attention on that–simply connect the power and SATA/IDE/SCSI interface. As far as physically connecting the SATA to the motherboard, since I’m using a very similar drive that I was replacing, I will want to plug the SATA cable into the same SATA port that the failing drive was on. Upon powering on, the BIOS RAID Interface came up immediately after POST stating the array has been broken. Now you can reinitialize your broken array here, which is where you originally set up the RAID in the first place. By selecting “Choose replacement drive and rebuild”, it allows you to select your newly installed HDD and rebuild the array with two easy steps.

Or you can choose “Continue to boot” and set up the array with the Via V-RAID Utility.

Setting it up with the Via V-Tech RAID Utility is also not that big of a ordeal. Looking at the top picture in the article, in the bottom left of the window we can click on “Add/Remove Spare Disk” to select our newly installed disk and then we can break the old array with “Remove Array” and then click “Create Array” to make a new array with the old drive and the new HDD. Simple as that. See RAID setup and troubleshooting isn’t as scary as it seems!

Summary

It is always a good idea to have a current backup before preforming any procedure that involves the array and data in any way. Strange things can happen when it is rebuilding the array causing data corruption, and without a backup to fall on, you could be in serious trouble. Any server that is handling sensitive data should avoid the RAID 0 setup as much as possible since it isn’t redundant like the other choices. Without a RAID Utility, it is increasingly harder to monitor the status of a remote server array and hard drive health. They are a necessity to keep your server out of dangerous territory. Granted, each BIOS RAID setup will be a little different but all function the same way. Research your particular one and use these tactics to assist you in rebuilding your array.